package day07;

import java.util.Random;

public class VerificationCode {
    public static void main(String[] args) {
        String code = generateVeriCode(4);
        System.out.println("验证码为"+code);
    }
    public static String generateVeriCode(int len){
        String code = "";
        char[] chs = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t',
                      'u','v','w','x','y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N',
                      'O','P','Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3','4','5','6','7',
                      '8','9','0'};
        Random rand = new Random();
        for (int i =1;i<=len;i++){
            //int index =(int)(Math.random()*chs.length);
            int index = rand.nextInt(chs.length);
            code+= chs[index];
        }
        return code;
    }
}
